Boulder's Water Supplyby Robin Ecklund

Photograph of first Boulder Reservoir taken between 1920 and
1930.
Copyright by the Denver Public Library. Visit the BASIN
Gallery for more information.

The Boulder Water System didn't stay simple for
long. We've gone from "shovel diplomacy" (if you didn't like what
someone was doing with the upstream water you went after them with a shovel!)
into an extraordinarily complex system of water law involving the federal,
state, and local governments, ditch companies, agriculture, industry, and
private individuals.

By 1862, 24 ditch companies had acquired rights to Boulder Creek
Water. The first ditches were dug in 1859, just one year after Thomas Aiken
and his group of goldseekers arrived in our area!

Colorado water policy began when George Coffin's corn on the St.
Vrain Creek died because the Left Hand Ditch Co. (with prior rights) diverted
the upstream water into Left Hand Creek. Coffin took the ditch company to
court. In 1892 the Colorado Supreme Court ruled in favor of the Left Hand
Ditch Company, saying that the company's right to divert water was superior
to George Coffin's claim. Most importantly the Court upheld the ditch company's
right to divert water into a different drainage system. This case set a precedent
in water law, and became known as the "first in time, first in right"
or "prior appropriation" water doctrine.

It is this policy that allows Boulder to utilize Western Slope water
from the Big Thompson/Windy Gap Project. Water is taken from the headwaters
of the Colorado River and then stored at Grand Lake, Shadow Mountain Lake
and Lake Granby. (The later two are reservoirs, and Grand Lake is the largest
natural lake in the state of Colorado.) The water is piped by tunnel through
the Continental Divide to Mary's Lake, Estes Lake, Carter Lake, and Horsetooth
Reservoir. The water from Carter Lake moves through the St. Vrain Supply Canal,
flows underground at Rabbit Mountain, moves through the Boulder Feeder Canal
into Boulder Reservoir or the Treatment Plant on 63rd Street, and finally,
after an incredibly long journey, it flows into homes in East Boulder.

Other communities in the Boulder Area, including Louisville, Erie,
Lafayette, Superior and Broomfield, also receive western slope water from
the Big Thompson/Windy Gap project, although many of these communities must
also augment this water with additional sources, including South Boulder and
Boulder Creek.

All in all, Boulder receives some 40% of its water supply from Arapaho
Glacier (now considered a snowfield rather than glacier) and the Silver Lake
Watershed, 40% from water stored in Barker Reservoir on Middle Boulder Creek,
and 20% from the Boulder Feeder Canal or the Boulder Reservoir.

Of course, "first in time, first in right" allows others
access to the Boulder creek watershed. Gross Reservoir behind Flagstaff and
Green Mountains is owned by the City of Denver Water District. Water from
the western slope is piped through the Continental Divide at the Moffat Tunnel
and, along with natural drainage from the South Boulder Creek watershed, is
stored in Gross Reservoir and captured and diverted from South Boulder Creek
to Denver in order to supply water to Denver homes and business.

Sources

Fact Sheet #1, Drinking Water Program,
City of Boulder.

Smith, Phyllis. (1986). History of the
Water Works of Boulder, CO, City of Boulder.

Clark, Ann (Fall, 1993). Images of Boulder
County. "Water."

From The Many Voices of the Boulder Creek Watershed, copyright 1996
by
The Naropa Institute. Used by permission.

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